This invention relates to an apparatus for cleaning floors and floor coverings. More particularly, the invention relates to an apparatus adapted for the cleaning of carpets through the use of foam cleaning agents.
Foam cleaning agents have been used to clean carpets for many years. While it is possible to perform foam cleaning operations manually, it takes less physical exertion and therefore is normally preferable to utilize an apparatus which will assure even application and removal of the foam, and at the same time provide means for vigorously agitating the carpet prior to removal of the foam, thus providing superior cleansing. Such apparatus have also attempted to remove the foam as soon as possible after application to prevent oversaturation of the carpet which can result in shrinkage, browning, mildew and excessive drying times. Due to difficulties inherent in conveying foam through closed conduits, such apparatus also include means for generating the foam.
Many such designs have been introduced. For example, U.S. Pat. No. 3,392,418 to Schowalter discloses a self-contained unit in which foam is generated through the utilization of a high pressure air stream acting upon a detergent feed tube. The air conveys droplets of detergent against a screen, thereby producing foam. The foam is permitted to drop downwardly, through slots, onto a cylindrical brush. The brush is disposed transversely across the apparatus, parallel to the floor, so that rotation of the brush conveys foam to the carpet and agitates the carpet. The foam is subsequently removed by one of two vacuum slots positioned to the front and rear of the brush.
There are several drawbacks with Schowalter's design. First, Schowalter requires means for generating pressurized air. Such means are heavy and bulky, include serious disadvantages when one goal is to provide a self-contained, easily maneuverable apparatus, and will add substantially to the cost of the unit. However, a second, more important, disadvantage of the use of pressurized air to generate foam is that the foam itself is of lower quality for cleaning purposes. The use of pressurized air results in a foam which is very light (a high air/liquid ratio). This minimizes the amount of cleaning fluid in the foam, and thereby decreases the effective cleansing achieved by the foam. Moreover, due to the light weight of the foam, there is a minimal amount of penetration into the carpet, thus resulting in only surface cleaning. In addition to the problems inherent in the use of light weight foam such as that generated by Schowalter's apparatus, foam formed through the use of pressurized air is often irregular in consistency. This introduces the possibility of streaking due to uneven saturation and cleaning of the carpet. This possibility of streaking is further advanced by yet another design flaw in Schowalter's apparatus, to wit, the fact that he utilizes a plurality of spaced slots to generate the foam and deposit it on the brush, thus necessarily relying upon the brush itself to evenly distribute the foam across its length. Since the brush only rotates and does not move axially, only a minimal amount of axial distribution takes place in the brush.
Due to the above-described problems in the generation and application of foam to the carpet, others have designed apparatus which use liquid cleaning agents. These apparatus are often referred to in the industry as "steam" cleaners. For example, U.S. Pat. No. 1,975,380 to Streich discloses an apparatus in which two nozzles spray liquid cleaner into a transversely disposed rotating brush. Streich's brush is intended to convey the liquid to the carpet, and agitate the carpet prior to removal of the liquid by transverse vacuum means. Streich's design results in the uneven distribution of cleaning liquid because his liquid would have a tendency to penetrate into the brush, saturating the brush after a certain period of time which could result in drainage from the brush to the carpet. This could produce serious streaking and overwetting problems.
This problem of overwetting, briefly mentioned above, is one which is inherent in all liquid (so-called "steam") cleaning operations. When cleaning liquid is brushed, sprayed, or otherwise deposited on the carpet, it tends to penetrate deeply into the carpet. While theoretically this could result in excellent deep cleaning action, liquid cleaning operations have a serious practical problem in that once the cleaning liquid has penetrated into the carpet, it is extremely difficult, if not impossible, to remove. Moreover, in passing through the upper layers of fibers, the liquid tends to absorb dirt and carry it down to the lower layers, where it remains. This minimizes the amount of dirt which can actually be removed from the carpet, and can result in shrinkage, mildew and browning. Moreover, all liquid (or steam) cleaning operations require substantial drying times, which is a serious disadvantage, particularly in commercial establishments.
A more recent U.S. Pat. No. 3,699,607, to Putt, utilizes a plurality of aligned nozzles to spray liquid cleaner (which the patent says is water) toward the floor near the engagement of a transversely disposed brush with the floor. Because Putt sprays the liquid cleaner toward the floor, his design could produce overwetting problems even more serious than those encountered by Streich.
It is thus an object of the present invention to provide an apparatus for cleaning carpets utilizing foam in order to overcome the aforementioned disadvantages inherent in the use of liquid cleaners. Another object is the provision of an apparatus for cleaning floor coverings which generates a dense, uniform quality foam, in order to achieve controlled penetration, superior cleansing, and which can remove the dirt-laden foam after a brief period of contact with the floor covering, thereby minimizing the possibility of overwetting. Yet another object of the present invention is to provide an apparatus which can deposit cleansing foam on a floor covering in an even pattern, and at the same time agitate the floor covering in order to ensure even, complete cleaning of the floor covering and to minimize streaking.
This invention responds to the drawbacks and limitations of the prior art by providing an apparatus which utilizes a transversely extending brush in conjunction with a plurality of foam producing nozzles which direct a spray of foam toward the brush, and vacuum means adapted to remove the foam and released dirt from the floor covering. The brush is rotatably mounted and is adapted to contact the floor covering when the apparatus is in its operating position. The apparatus includes front and back ends and the nozzles are positioned to the rear of the brush, to spray foam into the brush in a direction which is substantially parallel with the floor. Thus, rotation of the brush causes the foam to be brushed into the floor covering. The vacuum means include an intake extending transversely across the apparatus, forward of the brush, so that rearward movement of the apparatus permits the vacuum means intake to remove foam and released dirt from the floor covering. The nozzles are positioned such that the spray from each nozzle overlaps the spray from an adjacent nozzle. The spray patterns can be arranged such that the spray from each nozzle overlaps the proximal half of the spray from an adjacent nozzle, thereby ensuring double coverage of foam for substantially the entire length of the brush.
These and other features and advantages of the present invention will be apparent from the following description, appended claims and annexed drawings.